A foldable telescope golf cart has been commonly used by golfers for carrying the golf bag with clubs. In the prior art design (FIG. 1), the cart typically consists of an upper frame and a lower frame pivotably jointed; a pair of wheel assemblies attached to the lower frame; links interconnecting the wheel assemblies and the upper frame; and saddles fixedly attached to the lower frame for supporting and securing the golf bag. By rotating the upper frame at the pivot joint toward the lower frame, the cart frames and wheel assemblies are folded simultaneously to a compact size.
An ideal telescope golf cart shall be capable of maintaining the cart in a balanced position and having the entire weight of cart assembly imposed upon the wheels during traveling. The golfer shall not be subject to the weight of the cart assembly, and shah only be required to exercise negligible force against the wheel's rotational friction as he is pulling the cart. Such an ideal telescope golf cart is possible only if the center gravity (c.g.) of the cart assembly including the weight of golf clubs is maintained in line with the center line of the wheels at all time during traveling.
There are several factors affect the location of c.g. of the golf cart assembly: (1). The c.g. of the golf clubs which dominantly determines the c.g. location of the entire cart assembly; the c.g. location in a golf club is affected by the individual club's design and material; the c.g. of a golf club with a lighter graphite shaft is located closer to the club head than that of a golf club with a steel shaft; as the golf bag being placed on an inclined golf cart with the golf club heads in the upright position, the c.g. of the golf clubs is elevated. (2). The respective incline angle of the cart corresponding to the cart's initial standing position and traveling position; as the cart being rotated from its initial standing position to traveling position, the incline angle of the cart is decreased, and the c.g. of the cart assembly is shifted forward to the front end of the cart; the greater change in the incline angle, the further movement of the c.g. of the cart assembly. (3). The height of the golfer which determines the incline angle of the cart during traveling; a golfer with a shorter height requires a smaller incline angle of the cart to comfortably pull the cart, and therefore the c.g. of the cart could move further to the front and closer to the golfer.
It is understood that the above factors have been mostly overlooked in the prior art design of golf cart, and the golfer has no means of adjusting the c.g. location of the cart. This may be due to the fact that the foldability design requirement of the cart imposes certain limitations on the configuration of the cart. In the prior art design, the c.g. of the cart in a standing position is closely located behind the center line of the wheels. (FIG. 1 ) As the cart being changed to a traveling position, the incline angle of the cart is reduced, and the c.g. moves forward passing the center line of the wheels. (FIG. 2) As a result, the golfer is imposed upon the weight of the cart assembly, and must produce a upward force to balance the cart during cart pulling. In the prior art design, attempts have been made to make the length of the upper frame of the cart adjustable, which have little effect in balancing the cart. In fact, these attempts could have an adverse effect of moving the c.g. of the cart closer to the golfer, and consequently increasing the loads on the golfer.
After considering the above factors, the basic principal for the conceptual design of the present invention is developed as follows: Since both the golf cart and the golf bag rotate about the same degree when the cart is changed from its initial standing position to traveling position, it is advantageous to design a balancing mechanism capable of rotating the golf bag in the direction opposite to the cart's rotation to offset the effect of c.g. movement. For example, if the cart is required to rotate 30 degree counter clockwise from the initial standing position to the traveling position, the balancing mechanism should be capable of rotating the golf bag 30 degree clockwise before rotating the cart from the standing position to traveling position. As a result, the effect of c.g. movement of the cart assembly is mostly eliminated. Since the golf cart may be required to rotate to a different angle under a different condition, such a balancing mechanism should be able to adjust the rotation angle of the golf bag accordingly, and consequently position the c.g. of the cart assembly at the center line of the wheels.